Data processing: measuring – calibrating – or testing – Calibration or correction system – Circuit tuning
Reexamination Certificate
2002-11-27
2004-02-24
Nghiem, Michael (Department: 2863)
Data processing: measuring, calibrating, or testing
Calibration or correction system
Circuit tuning
Reexamination Certificate
active
06697749
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a correction method for correcting electrical characteristics of electronic components measured by an actual measuring system with measured results, which do not agree with a reference measuring system, to electrical characteristics assumed to be obtained by the reference measuring system; a quality checking method using the correction method for electronic components; and a characteristic measuring system for performing the correction method on electronic components.
2. Description of the Related Art
In measuring electrical characteristics of electronic components, sometimes, the same electronic component or the same kind thereof is measured by a plurality of measuring systems, such as a measuring system set up in a site for an electronic component manufacturer and another measuring system set up in a site for a user of the electronic components.
Because measurement errors are different from those in each measuring system in such a case, the precision of measurement reproducibility is low, so that a problem arises from inconsistency of measured results for the same electronic component or the same kind thereof.
Such measurement errors are comparatively low in the electrical characteristic measurement in a low frequency region, so that there is not much problem on this point. Whereas, in a high frequency region of 100 MHz or more, the measurement errors between measuring systems are large, so that in order to improve the precision of measurement reproducibility, calibration using an absolute correction method is performed especially in a high frequency region of several GHz or more.
A standard device is prepared in advance in that an instrument having a target electrical characteristic precisely identified, such as an open/short/load/through, an example of which is the model 85052B manufactured by Agilent Technologies Company. Various measurements of this standard device by each measuring system identify the error factor of each measuring system. Then, the calibration such as a high-accuracy full two-port correction method is performed thereon to eliminate the identified error factor, improving the precision of measurement reproducibility (such a correction method is referred to as an absolute correction method below).
In such a manner, a measuring system can improve the precision of measurement reproducibility by performing the high-accuracy calibration using the standard device mentioned above. However, such calibration can be performed on only an electronic component with a coaxial form (referred to as a coaxial-type electronic component below) so as to measure precisely.
Whereas, the calibration mentioned above has been difficult to perform on an electronic component with a non-coaxial form (referred to as a noncoaxial-type electronic component below). The reason thereof is described below.
A standard device for noncoaxial-type electronic components is extremely difficult to be manufactured to have substantially the same performance as that for coaxial-type electronic components, and manufacturing cost for such a standard device becomes extremely large. Moreover, even if the standard device is manufactured, it is difficult to specify electrical characteristics thereof in high accuracy.
Furthermore, even if a standard device for noncoaxial-type electronic components is prepared, in a measuring system capable of performing the high-accuracy calibration (such as the full two-port correction method), the standard device capable of performing the calibration mentioned above is limited to the instrument to achieve the value (typically, the open/short/load/through), which cannot be achieved unless the component is of a coaxial-type. By such reasons, the calibration mentioned above is difficult to be performed on noncoaxial-type electronic components.
In performing a TRL correction method, a kind of calibration, a standard device (typically, a standard device of a through/reflection/line) for noncoaxial-type electronic components such as waveguides and microstrip lines may be easily manufactured. However, even in the standard device suitable for the TRL correction method, it is difficult to specify electrical characteristics thereof in high accuracy.
As described above, in the measurement of electrical characteristics of noncoaxial-type electronic components, it is difficult to improve measurement accuracy by performing the calibration thereon based on the absolute correction method. Therefore, up to now, in the measurement of electrical characteristics of noncoaxial-type electronic components, the calibration at junction points of the electronic component is not performed but the measurement is performed in a state of being attached to a measurement fixture, as will be described below.
A measurement fixture is prepared, which has coaxial input-output terminals for a measuring system while having noncoaxial input-output terminals for a noncoaxial-type electronic component. This measurement fixture is electrically connected to a piece of coaxial cable, which is connected to input-output terminals of the measuring system. Then, the noncoaxial-type electronic component is mounted on the measuring system so that electrical characteristics of the component are measured. In addition, it is preferable that the calibration such as a full two-port correction method be performed on the coaxial cable connected to the input-output terminals of the measuring system up to the tip end.
In such an electrical characteristic measurement method for noncoaxial-type electronic components using the measurement fixture, calibration cannot be performed by including the measurement fixture. Therefore, the reproducibility of measured results is low. In order to increase the reproducibility of the measured results, the following adjustments of the measuring system are performed.
In this adjustment, one measuring system is regarded as a reference measuring system having a reference measurement fixture and the other is regarded as an actually measuring system having an actual measurement fixture, so that the actual measurement fixture of the actually measuring system is adjusted so as to bring the measured result from the actually measuring system to that from the reference measuring system. Specifically, electrical characteristics of an arbitrary sample (electronic component) are measured by the reference measuring system; electrical characteristics of the same sample are measured by the actually measuring system, and then, the actual measurement fixture is adjusted so that both the measured results are equalized. The adjustment is specifically performed as follows.
The actual measurement fixture is arranged that a coaxial connector to be connected to a measuring system is attached to a printed circuit board having input-output terminals to be connected to a sample, which are disposed at a wiring end-portion on the substrate surface. In the actual measurement fixture structured as above, adjustment is performed as follows. While part of printed wiring on the printed circuit board being cut off, or solder being put on the printed wiring, changes in the measured results are measured, and the treatment is finalized after the same electrical characteristics as those of the measured results in the reference measuring system are obtained.
The measuring method of electrical characteristics of electronic components described above has the following problems for both measurements of coaxial-type electronic components and noncoaxial-type electronic components.
In measuring method of coaxial-type electronic components, although the reference device necessary for the calibration is available, it is expensive, so that there is a problem that the cost of the calibration is increased, and by extension, the cost for measuring electrical characteristics of electronic components is increased.
In measuring method of noncoaxial-type electronic components, because the adjustment method of the actual measurement fixture mentioned above is not
Murata Manufacturing Co. Ltd.
Nghiem Michael
Ostrolenk Faber Gerb & Soffen, LLP
LandOfFree
Correction method of measurement errors, quality checking... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Correction method of measurement errors, quality checking..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Correction method of measurement errors, quality checking... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3298175